Health professionals are reporting progress in the application of improvement principles and methods to clinical care. One year ago we wrote, "Continuous improvement is a reality in clinical medicine.... Examples of improvement in direct patient care finally have emerged in the literature."1 The pace is increasing. A recent MEDLINE search of the entries "total quality management" combined with "clinical" from 1985 to 1994 revealed 125 English-language citations, with 91 written from 1991 through 1994. A similar search of the entries "continuous quality improvement" combined with "clinical" uncovered 82 articles, all but 15 published after 1991.

The most successful efforts combine professional knowledge (such as pathogenesis and therapeutics) with "knowledge for improvement," as described by Batalden and Nolan2 and elaborated on by Batalden and Stoltz.3 Knowledge for improvement incorporates an understanding of systems, statistical variation, the psychology of work and change, and the scientific method. We will focus